Hi all,
I want to know whether optical fibre based networks are fully digital in
nature.
The tarditional LAN needs a PHy to to the DSP and conversion from analog to
digital and vice versa. Does the optical fiber based architecture need any
such conversion?
regards,
amitr0
Wow, I think that’s a new standard in off-topic posts…
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of A P
Sent: Tuesday, February 06, 2007 1:53 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] optical fibres
Hi all,
I want to know whether optical fibre based networks are fully digital in nature.
The tarditional LAN needs a PHy to to the DSP and conversion from analog to digital and vice versa. Does the optical fiber based architecture need any such conversion?
regards,
amitr0
— Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256 To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer
A P wrote:
I want to know whether optical fibre based networks are fully digital
in nature.The tarditional LAN needs a PHy to to the DSP and conversion from
analog to digital and vice versa. Does the optical fiber based
architecture need any such conversion?
Why does it matter? The real world is analog in nature (ignoring the
quantum world), so even though the fiber adapter is using digital
signals to turn the fiber LEDs on and off, the light inside the fiber is
certainly analog.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
It is ‘digital’ because the information modulated on the optical link can
only assume a discrete set of symbol states (at the most simiplistic, 1 or
0). The system does not allow for ‘maybe’ or ‘mostly’ or 1/2 or any other
information state that could be described in an analog system. Analog
systems are perturbed by noise. In digital systems it is described as
errors. The distinction is important: The digital system has a concept of
‘correct value’ by which one can therefore derive that an particular value
is ‘wrong’ (error). An analog system, on the other hand, is just noisy.
So, if the system is ‘bits in bits out’ it is digital no matter what analog
transmission system is used to carry the modulated signal (light, radio,
electric current, mechanical vibration etc.) It becomes digital as soon as
you enforce the requirement that a hard decision is made at the decoder as
to ‘right or wrong’ for a symbol value.
And yes, they have a Phy.
Cheers,
Dave Cattley
Consulting Engineer
Systems Software Development
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Tim Roberts
Sent: Wednesday, February 07, 2007 2:01 PM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] optical fibres
A P wrote:
I want to know whether optical fibre based networks are fully digital
in nature.The tarditional LAN needs a PHy to to the DSP and conversion from
analog to digital and vice versa. Does the optical fiber based
architecture need any such conversion?
Why does it matter? The real world is analog in nature (ignoring the
quantum world), so even though the fiber adapter is using digital signals to
turn the fiber LEDs on and off, the light inside the fiber is certainly
analog.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer